Turbine Driven Hammer that Oscillates at a Constant Frequency

ABSTRACT

In one aspect of the present invention a hammer assembly comprises a substantially coaxial jack element with a distal end extending beyond a working face of a drill bit. A porting mechanism within the bore comprises a first and second disc substantially contacting along a flat interface substantially normal to the axis of rotation. The first disc is attached to a turbine which is adapted to rotate the first disc with respect to the second disc. The first disc comprises a first set of ports adapted to align and misalign with a second and third set of ports in the second disc. As the first disc rotates, the sets of ports are adapted to route a drilling fluid into a piston chamber where the porting mechanism causes the jack element to repeatedly extend further beyond the working surface of the drill bit at a constant frequency.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation-in-part of U.S. patent application Ser. No. 12/415,188 which is a continuation-in-part of U.S. patent application Ser. No. 12/178,467 which is a continuation-in-part of U.S. patent application Ser. No. 12/039,608 which is a continuation-in-part of U.S. patent application Ser. No. 12/037,682 which is a continuation-in-part of U.S. patent application Ser. No. 12/019,782 which is a continuation-in-part of U.S. patent application Ser. No. 11/837,321 which is a continuation-in-part of U.S. patent application Ser. No. 11/750,700. which is a continuation-in-part of U.S. patent application Ser. No. 11/737,034 which is a continuation-in-part of U.S. patent application Ser. No. 11/686,638 which is a continuation-in-part of U.S. patent application Ser. No. 11/680,997 which is a continuation-in-part of U.S. patent application Ser. No. 11/673,872 which is a continuation-in-part of U.S. patent application Ser. No. 11/611,310.

U.S. patent application Ser. No. 12/178,467 is also a continuation-in-part of U.S. patent application Ser. No. 11/278,935 which is a continuation-in-part of U.S. patent application Ser. No. 11/277,294 which is a continuation-in-part of U.S. patent application Ser. No. 11/277,380 which is a continuation-in-part of U.S. patent application Ser. No. 11/306,976 which is a continuation-in-part of U.S. patent application Ser. No. 11/306,307 which is a continuation-in-part of U.S. patent application Ser. No. 11/306,022 which is a continuation-in-part of U.S. patent application Ser. No. 11/164,391.

U.S. patent application Ser. No. 12/178,467 is also a continuation-in-part of U.S. patent application Ser. No. 11/555,334.

All of these applications are herein incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

This invention relates to the field of percussive tools used in drilling. More specifically, the invention deals with a downhole jack hammer actuated by drilling fluid.

U.S. Pat. No. 7,073,610 to Susman, which is herein incorporated by reference for all that it contains, discloses a downhole tool for generating a longitudinal mechanical load. In one embodiment, a downhole hammer is disclosed which is activated by applying a load on the hammer and supplying pressurizing fluid to the hammer. The hammer includes a shuttle valve and piston that are moveable between first and further position, seal faces of the shuttle valve and piston being released when the valve and the piston are in their respective further positions, to allow fluid flow through the tool. When the seal is releasing, the piston impacts a remainder of the tool to generate mechanical load. The mechanical load is cyclical by repeated movements of the shuttle valve and piston.

U.S. Pat. No. 6,994,175 to Egerstrom, which is herein incorporated by reference for all that it contains, discloses a hydraulic drill string device that can be in the form of a percussive hydraulic in-hole drilling machine that has a piston hammer with an axial through hole into which a tube extends. The tube forms a channel for flushing fluid from a spool valve and the tube wall contains channels with ports cooperating with the piston hammer for controlling the valve.

U.S. Pat. No. 4,819,745 to Walter, which is herein incorporated by reference for all that it contains, discloses a device placed in a drill string to provide a pulsating flow of the pressurized drilling fluid to the jets of the drill bit to enhance chip removal and provide a vibrating action in the drill bit itself thereby to provide a more efficient and effective drilling operation.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention, a hammer assembly comprises a substantially coaxial jack element with an axis of rotation of a drill bit. The jack element comprises a distal end that extends beyond a working face of a drill bit. A porting mechanism within the bore comprises a first and second disc substantially contacting along a flat interface substantially normal to the axis of rotation. The first disc is attached to a turbine which is adapted to rotate the first disc with respect to the second disc. The first disc comprises a first set of ports adapted to align and misalign with a second and third set of ports on the second disc. As the first disc rotates, the sets of ports route drilling fluid into a piston chamber adjacent to the second disc. The porting mechanism causes the jack element to extend further beyond the working surface of the drill bit at a constant frequency.

The first and second set of ports may be aligned which may route drilling fluid through a first channel to the proximal end of the piston chamber where the piston in the chamber may be in mechanical communication with a jack element at the distal end of the chamber. In some embodiments, the mechanical communication comprises a rigid mechanical connection, an intermittent mechanical connection, a hydraulic connection, or a combination of these connections. The first and third set of ports may also be aligned which may route drilling fluid through a second channel to the distal end of the piston chamber. The drilling fluid may then direct the piston towards the proximal end of the chamber forcing the drilling fluid in the proximal end to flow through a set of exhaust ports of the first disc.

The exhaust ports may have a characteristic to absorb energy from redirecting the drilling fluid flow. This characteristic may result from the geometry of the exhaust ports which may include expanding diameters from entrance to exit, an exit not parallel to the entrance, an exit on the outer diameter of the first disc, or any combination of these characteristics. This characteristic may resist the turbine's rotation at a non-linear rate with respect to the drilling fluid flow.

In some embodiments, the hammer assembly may comprise a lubrication system. The lubrication system may comprise a shaft that extends from the second disc to a lubricant reservoir adjacent to the turbine. The lubrication system may also comprise a bypass channel that is formed adjacent to the turbine. The channel extends from the lubricant reservoir to beyond a sealing element located adjacent to the first disc. The bypass channel may comprise a set of tortuous paths which may limit the amount of drilling fluid allowed to flow. The drilling fluid directed to the reservoir may apply a force to direct the lubricant along the shaft while the drilling fluid directed beyond the sealing element may create a pressure balance that limits the amount of lubricant that flows through the sealing element.

In some embodiments, the constant frequency may be achieved through a combination of the turbine and the exhaust ports.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective diagram of an embodiment of a down-hole tool string suspended in a bore-hole.

FIG. 2 is a cross-sectional diagram of an embodiment of a drilling assembly.

FIG. 3 is a cross-sectional diagram of another embodiment of a drilling assembly.

FIG. 4 is a partial cross-sectional diagram another embodiment of a drilling assembly.

FIG. 5 is a diagram of an embodiment of a relationship between the force of the turbine and the force of the exhaust ports.

FIG. 6 is a perspective top diagram of an embodiment of the first disc.

FIG. 7 is a perspective bottom diagram of an embodiment of the first disc.

FIG. 8 is a perspective top diagram of an embodiment of the second disc.

FIG. 9 is a perspective bottom diagram of an embodiment of the second disc.

FIG. 10 is a cross-sectional diagram of an embodiment of a lubrication system.

FIG. 11 is a sectional diagram of an embodiment of a turbine blade.

FIG. 12 is a sectional diagram of another embodiment of a turbine blade.

FIG. 13 is a sectional diagram of another embodiment of a turbine blade.

FIG. 14 is a sectional diagram of another embodiment of a turbine blade.

FIG. 15 is a sectional diagram of another embodiment of a turbine blade.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

FIG. 1 is a perspective diagram of an embodiment of a tool string 100 suspended by a derrick 101 in a borehole 106. A drilling assembly 102 is located at the bottom of the bore hole 106 and comprises a drill bit 104. As the drill bit 104 rotates downhole the tool string 100 advances farther into the earth. The drill string 100 may penetrate soft or hard subterranean formations 105.

FIG. 2 is a cross-sectional diagram of an embodiment of a drilling assembly 102. The drilling assembly 102 may comprise a shank 201 and a working face 203 with a plurality of cutting elements 205 adapted to advance the drill bit further into a formation. The drilling assembly may comprise at least one turbine 207 disposed within the bore and adapted to interact with a drilling fluid.

The drilling assembly may further comprise a porting mechanism 209 that directs at least some of the drilling fluid to move the jack element 223. The porting mechanism may comprise a first and second disc 211, 213. The first and second disc 211, 213 may contact along a substantially flat interface that is substantially normal to the drilling assembly's an axis of rotation. The first disc 211 may be rigidly connected to the turbine 207, so that the first disc rotates as the turbine rotates. A piston chamber 219 may be adjacent to the second disc and may contain a piston 221 capable of transferring energy into the jack element 223, which is located at the distal end of the piston chamber 219. The first and second disc 211,213 may comprise a first and second set of ports 215, 217, which, when aligned, may route drilling fluid into the proximal end of the piston chamber 219. The drilling fluid may apply a force on the piston 221 that causes the piston to move towards the working face of the drill bit. The piston may impact against a proximal end of the jack element transferring its kinetic energy through the jack element into the formation.

FIG. 3 discloses an alignment of the first set 215 of ports with a third set 301 of ports which may permit drilling fluid to pass through the porting mechanism 209 to the distal end of the piston chamber 219. This drilling mud may apply a force to the piston 221 pushing the piston 221 back towards the proximal end. The movement of the piston 221 may unload the jack element 223. In some embodiments, the retreat of the piston may cause a retraction of the jack element away from the formation.

FIG. 4 discloses the porting mechanism, channels, and piston chamber of the assembly rotated by 90 degrees. As the drilling fluid flows past the turbine 207, the turbine rotates and the first and second set of ports align 215, 217. When the ports are aligned the drilling fluid passes through a channel 220 to the distal end of the piston chamber 219 and pushes the piston 221 back towards the proximal end. This may cause the fluid in the proximal end of the piston chamber to be forced through the exhaust ports 405. Because of the exhaust ports' geometry, the drilling fluid forced through the exhaust ports 405 may cause a force to resist the rotation of the turbine 207.

The geometry of the exhaust ports may comprise a narrow diameter substantially parallel to the axis of rotation and adjacent to the second disc. This diameter may expand rapidly with an exit substantially perpendicular to the axis of rotation. Energy may be absorbed when the drilling fluid is forced to change direction and exit the exhaust ports. The energy in the drilling fluid may be absorbed into the system to resist the rotation of the turbine when the drilling mud is forced to turn sharply.

FIG. 5 discloses a graph of forces applied by the turbine 207 and the exhaust ports 405 that shows an embodiment of the relationship between the forces exerted by the turbine and the exhaust ports. The bottom axis 550 discloses the drilling flow rate in gallons per minute while the side axis 551 discloses the amount of force produced. The black line 552 discloses the rotational force produced by the turbine. The gray line 553 discloses the resistive force created by the exhaust ports. The dashed line 554 discloses the combination of these two forces. As the amount of drilling fluid increases, the turbine 207 has an increase in rotational force against the rotation, but the resistive force from the exhaust ports also increases. To some degree, the resistive force cancels out the proportional turbine force, thus making the total energy into the system more constant. This may cause the turbine 207 rotation to remain constant over a wider range of drilling flow rates.

FIGS. 6 and 7 are perspective views of a top and bottom side 703, 603 of the first disc 211. The ports of the first set 215 may be spaced evenly around the outer diameter of the disc. The exhaust ports 405 may be also spaced evenly around the outer diameter of the disc and between the ports of the first set 215. The first set of ports 215 may have a wide diameter 601 on the top side 603 that may become significantly narrower before reaching the bottom side 703. The exhaust ports may have a narrow diameter on the bottom side 603 that expands to a much wider diameter with an exit on the outer edge of the disc 605.

FIGS. 8 and 9 are perspective views of a top and bottom side 801, 901 of the second disc 213. The ports of the second set 217 may be spaced evenly around the diameter of the disc, with the ports of the third set 303 spaced evenly between each port of the second set. The second set of ports may comprise nozzles that may allow fluid to flow to the working face 203 of the drill bit effectively bypassing the hammer assembly. If the piston chamber 219 were to fail, the nozzles 803 may provide an outlet to prevent pressure backup and possible harm to the assembly. The second set of ports may be angled to facilitate the flow of drilling fluid into the piston chamber 219. The third set of ports 303 may comprise a large diameter completely through the disc.

FIG. 10 is a cross-sectional diagram of a lubrication system. The lubrication system may have a first set of tortuous paths 1001 adjacent to the turbine 207 and a second set of tortuous paths 1003 adjacent to the first disc 211. The lubrication system may also have a bypass channel 1005 in communication with a lubrication reservoir 1009 and bypasses sealing elements 1007 of the system. The drilling fluid passing into the lubrication reservoir 1009 may push lubricant along a shaft 1011 that extends to a first and second bearing 1013, 1015. The first and second bearing 1013, 1015 may comprise a thrust and a ball bearing. The thrust and ball bearing may help support radial and axial loads as well as reducing rotational friction. The drilling fluid passing to beyond the sealing element 1007 creates a pressure balance which regulates the amount of lubrication that exits the shaft 1011. The regulation of lubrication, may keep the bearings well lubricated over an extended period of time which may increase the amount of time that can pass before the lubrication reservoir 1009 needs to be refilled.

FIG. 11 discloses a cross section 1100 of a turbine blade which may be used in the present invention. The turbine may also comprise an overall characteristic which causes the turbine to stall when the rotor exceeds a maximum rotational velocity. The blade section 1100 may comprise a trip 1101 that may be adapted to cause the blade to stall at the predetermined velocity. The trip 1101 may comprise a concavity 1102 formed in a leading portion 1108 of the blade section 1100. The concavity 1102 may separate a first and second upper camber 1103 of the leading portion 1108 of the section. The first and second upper cambers 1103 may comprise substantially equivalent curvatures. The concavity 1102 may also comprise an acute transition 1107 from the first to the second camber. The acute transition 1107 may form an angle of at least 75 degrees.

FIG. 12 discloses a spiral blade section 1210 that may also be used with the present invention, also comprises a stalling trip.

FIG. 13 discloses a straight blade section 1311 that also comprises a truncated trailing portion 1312.

FIG. 14 discloses a blade section 1311 with a trailing portion 1413 comprising a profile segment 1414 that forms an angle 1415 greater than 25 degrees.

FIG. 15 discloses a blade section 1311 with a trailing portion 1413 also comprising a concavity 1516.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention. 

1. A hammer assembly, comprising; a jack element substantially coaxial with an axis of rotation of a drill bit, the jack element comprises a distal end extending beyond a working face of the drill bit; a porting mechanism within the bore comprising a first and second disc substantially contacting along a flat interface substantially normal to the axis of rotation; the first disc attached to a turbine which is adapted to rotate the first disc with respect to the second disc; the first disc comprises a first set of ports adapted to align and misalign with a second and third set of ports of the second disc as the first disc rotates, the sets of ports are adapted to route a drilling fluid into a piston chamber; wherein the porting mechanism causes the jack element to repeatedly extend further beyond the working surface of the drill bit at a constant frequency.
 2. The hammer assembly of claim 1, wherein the drilling fluid is routed by the first and second set of ports through a first channel to the proximal end of the piston chamber adjacent to the second disc.
 3. The hammer assembly of claim 2, wherein a piston in the piston chamber is in mechanical communication with a jack element at the distal end of the piston chamber.
 4. The hammer assembly of claim 3, wherein the mechanical communication comprises a rigid mechanical connection, an intermittent mechanical connection, a hydraulic connection, or a combination thereof.
 5. The hammer assembly of claim 1, wherein the drilling fluid passes through a second channel adjacent the aligned first and third set of ports, which leads to the distal end of the piston chamber.
 6. The hammer assembly of claim 5, wherein drilling fluid directs the piston towards the proximal end of the chamber.
 7. The hammer assembly of claim 2, wherein when drilling fluid is forced out of the piston chamber, the fluid exits the proximal end of the piston chamber through a set of exhaust ports of the first disc.
 8. The hammer assembly of claim 7, wherein the set of exhaust ports have the characteristic to absorb energy from redirecting the drilling fluid flow.
 9. The hammer assembly of claim 8, wherein the characteristic to absorb energy is dependent on the geometry which may include expanding diameters from entrance to ext, an exit not parallel to the entrance, an exit on the outer diameter of the first disc, or any combination thereof.
 10. The hammer assembly of claim 9, wherein the characteristic to absorb energy causes a resistance which increases at a non-linear rate with an increase in drilling fluid flow.
 11. The hammer assembly of claim 1, wherein the constant frequency is predetermined by a ratio between impact energy of the jack element and wear on the jack element.
 12. The hammer assembly of claim 1, wherein the constant frequency is achieved through a combination of turbine blade geometry and exhaust ports geometry.
 13. The hammer assembly of claim 1, wherein the second set of ports comprises a smaller flow area, then the first set of ports.
 14. The hammer assembly of claim 1, wherein the hammer assembly comprises a lubrication system.
 15. The hammer assembly of claim 15, wherein the lubrication system comprises a shaft that extends from the second disc to a lubricant reservoir adjacent to the turbine.
 16. The hammer assembly of claim 15, wherein the lubrication system comprises a bypass channel that is formed adjacent to the turbine and extends to beyond a sealing element located adjacent to the first disc and also extends to the lubricant reservoir.
 17. The hammer assembly of claim 17, wherein the bypass channel comprises a set of tortuous paths which limit the amount of drilling fluid allowed to pass.
 18. The hammer assembly of claim 17, wherein the drilling fluid directed to the reservoir applies a force to direct the lubricant along the shaft.
 19. The hammer assembly of claim 17, wherein the drilling fluid directed to beyond the sealing element creates a pressure balance which limits the amount of lubricant that passes through the sealing element. 